This invention relates to luminaries such as street lamps, and more particularly to a starting aid device for a luminaire which automatically turns the luminaire on and off, can sense a faulty condition and can communicate that condition locally or to a remote location.
Servicing a luminaire such as a single street light can cost $100 or more on busy roads, and in busy areas. Moreover, since there are 60,000,000 street lights in the United States alone, the cost of servicing high pressure sodium (HPS) street lights cycling towards the end of their useful life is severe. The phenomena of cycling of HPS lamps as they age from use is the result of the electrode material being plated off the electrodes and then being deposited on the inside of the arc tube. This makes the tube darken and traps more heat inside the arc tube. As a result, an increased voltage is required to keep the lamp ignited or ionized. When the voltage limit of the ballast is reached, the lamp extinguishes by ceasing to ionize. The lamp must then cool down for several minutes before an attempt at re-ignition can be made. The result is xe2x80x9ccyclingxe2x80x9d, in which the worn out lamp keeps trying to stay lighted. The voltage limit is reached again, the lamp extinguishes, and then after an approximately one-two minute cool down period, the arc tube re-ignites and the light output increases again and until the voltage limit is reached whereupon the lamp extinguishes yet again. This repetitive on and off process is called cycling.
Cycling can waste electricity, cause radio frequency interference (RFI) which adversely affects communication circuits, radios, and televisions in the area, and may adversely effect and prematurely wear out the ballast, starter, and photocontroller.
For example, if an HPS lamp undergoes cycling for a few nights before it is finally serviced and replaced, the ballast or starter can also be damaged or degraded. However, when the HPS lamp is replaced, such damage or degradation might not be detected. Consequently, additional service calls must then be made to service these problems. The ballast and starter components are more expensive than the lamp or the photocontroller.
The cycling problem is well documented, but so far the only solutions offered are to replace the HPS lamps and luminaires with less efficient mercury lamps and luminaires or to reconfigure the photocontroller with a special fiber optic sensor which senses light from the lamp and sends a signal to a microprocessor to indicate whether the lamp is on or off. After three on/off cycles, the microprocessor turns the lamp off and turns on a red strobe light which can be seen from the street. Unfortunately, this prior art solution requires modifications to the existing light fixture (e.g. a hole must be drilled in the fixture housing) and the use of an expensive fiber optic sensor.
Another problem with all luminaries including HPS or other types of lamps is the cost involved in correcting the cycling problem and other faults such as a lamp out condition. For example, a resident reports a lamp out or a cycling condition. However, by the time the repair personnel arrives several hours later, the lamp may have cycled back on. Considering the fact that the lamp pole may be 25-35 ft. high, repair personnel can waste a considerable amount of time checking each lamp in the area. Also, repair and maintenance personnel may not be able to service a given residential area until daylight hours when all of the street lights are off by design.
It is therefore an object of this invention to provide a starting aid circuit for a lamp which can detect a faulty condition.
It is a further object of this invention to provide such a starting aid circuit which is microprocessor-based.
It is a further object of this invention to provide such a starting aid circuit which prevents hot restriking of a cycling or a dead lamp.
It is a further object of this invention to provide such a starting aid circuit which communicates that a fault in the lamp has occurred.
It is a further object of this invention to provide such a starting aid circuit which can communicate such a condition to a worker on the ground.
It is a further object of this invention to provide such a starting aid circuit which can communicate a faulty condition to a remote location.
It is a further object of this invention to provide such a starting aid circuit which automatically turns on and off in response to daytime and nighttime lighting conditions.
It is a further object of this invention to provide such a starting aid circuit which also turns the lamp off.
It is a further object of this invention to provide such a starting aid circuit which can detect whether the lamp is on or off.
It is a further object of this invention to provide such a starting aid circuit which can detect cycling of the lamp.
It is a further object of this invention to provide such a starting aid circuit which reduces maintenance of the lamp.
It is a further object of this invention to provide such a starting aid circuit which prolongs the life of the lamp.
It is a further object of this invention to provide such a starting aid circuit which is cost efficient to produce.
The invention results from the realization that a truly effective luminaire starting aid device can be obtained by providing a trigger circuit including a feedback loop that supplies a trigger voltage to the lamp and monitors the voltage of the lamp to determine if it has indeed started. If the lamp does not start, a microprocessor that controls the trigger circuit instructs the trigger circuit to repeat attempts to start the lamp a predetermined number of times, after which, if the lamp does not start, a faulty condition of the lamp is communicated either locally at the site of the luminaire or to a remote location.
This invention features a starting aid for a luminaire including a device for detecting a load drawn by or voltage across a lamp, a microprocessor, responsive to the means for detecting, for controlling start-up of the lamp, a power supply for operating the microprocessor and a trigger circuit, responsive to the microprocessor, for turning on the lamp.
In a preferred embodiment of the invention, the starting aid circuit may further be programmed to detect a condition of the lamp in response to the load drawn or voltage across the lamp. The starting aid circuit may further include means, responsive to the microprocessor, for indicating the occurrence of the condition detected. The starting aid circuit may further include a photo controller for automatically turning the lamp on during periods of darkness and off during periods of daylight and means, responsive to the microprocessor, for shunting the lamp to turn off the lamp. The means for detecting may include a voltage divider. The trigger circuit may include a SIDAC circuit for turning on the lamp and a relay circuit, responsive to the microprocessor, for enabling the SIDAC circuit. the trigger circuit may further include an opto-coupler, responsive to the microprocessor, for enabling the SIDAC circuit. The power supply may include a full wave rectifier and/or a half wave rectifier. The trigger circuit may further include a TRIAC circuit, responsive to the microprocessor, for enabling the SIDAC circuit. The starting aid circuit may further include means, responsive to the microprocessor, for shunting the lamp to turn off the lamp. The means for shunting may include a relay circuit, responsive to the microprocessor, for shorting the lamp. The means for shunting may include a TRIAC circuit or another silicon device such as a SCR circuit, responsive to the microprocessor, for shorting the lamp. The means for indicating may include a visual alarm, an audible alarm and/or a transmitter for transmitting the detected condition to a location. The condition may be a lamp dead condition and/or a cycling condition.
This invention also features a diagnostic starting aid for a luminaire including means for detecting a load drawn by or voltage across the lamp, a microprocessor, responsive to the means for detecting and the photocontroller, for controlling start-up of the lamp, the microprocessor programmed to detect a condition of the luminaire in response to the load drawn, a power supply for operating the microprocessor, a trigger circuit, responsive to the microprocessor, for turning on the lamp and means, response to the microprocessor, for indicating the occurrence of the condition detected.
This invention also features an automatic aid for a lamp including a photocontroller for automatically turning the lamp on during periods of darkness and off during periods of daylight, means for detecting a load drawn by or voltage across the lamp, a microprocessor, responsive to the means for detecting and to the photocontroller, for controlling start-up of the lamp, a power supply for operating the microprocessor and a trigger circuit, responsive to the microprocessor, for turning on the lamp.
In the preferred embodiment, the automatic starting aid may further include means, responsive to the microprocessor, for shunting the lamp to turn off the lamp. The microprocessor may be programmed to detect a condition of the lamp in response to the load drawn, further including means, responsive to the microprocessor, for indicating the occurrence of the condition detected.
This invention also features a starting aid including a trigger circuit for supplying a trigger voltage pulse to a lamp in response to the presence of a line voltage signal supplied by a photodetector, a feedback circuit for detecting the lamp voltage and means, responsive to the line voltage signal and the feedback circuit, for comparing the voltage on the lamp to a nominal voltage level for disabling the trigger circuit and terminating the trigger voltage pulse in the presence of a lamp cycling or lamp out condition.
In the preferred embodiment, the means for comparing may include a processor programmed to determine when the lamp voltage switches between a nominal voltage level and a non-nominal voltage level N times indicative of a lamp cycling condition. N may be 5. The means for comparing may include a processor programmed to determine when the voltage on the lamp falls to reach a nominal voltage level after M trigger voltage pulses. M may be 2. The starting aid may further include means, responsive to the line voltage signal, for supplying to the trigger circuit a series of trigger pulses at predetermined portions of the line voltage signal. The means for supplying may include a microprocessor programmed to determine a zero crossing point of the line voltage signal and to output the series of pulses when the line voltage signal reaches 90xc2x0 and 270xc2x0. The trigger circuit may include a transformer which is activated by the series of trigger pulses and in response produces a lamp starting voltage to the lamp.